In my 2 transfers through CDG en route to Athens, I recall (with shudders) the ordeal of making it to my onward flight. As others say, you go OUT of the secure area (there is no way to stay within it), and then have to find your way to the airport wing that has your onward fllight. During one transfer we had only 75 minutes; some people were led by an air france staffer with a flag, but we were not. No one helped they pretended not to understand our (college-era) French; in fact, the 2 women at the "Information" desk ignored us, except for mocking us to one another. We were sent to a shuttle bus that wended its way (slowly) around the outer part of the airport, stopping at different wings (the place is like an octopus). Seeing that we would not make it in time to our "Leg," we got off, and RAN for perhaps half mile thru the maze. Entering security (long line) we then were the last to board our plane. As we pulled out of the gate, I looked out of the window, and saw the shuttle bus finally arriving.
When I was forced to use CDG again, I chose a flight that had a 3.5 hour layover. Even then I would almost rather use ANY other European Airport for a plane-change.